Time-frequency transform vs. Fourier transform for radar imaging

Conventional radar imaging systems use the Fourier transform for reconstruction of radar images. To use the Fourier transform adequately, some restrictions must be applied. Due to target´s motion and manoeuvring, the reconstructed image by using Fourier transform becomes smeared. Therefore, some sophisticated motion compensation procedures must be applied to produce a clear image. However, the restrictions of Fourier transform can be lifted if a high resolution time-frequency transform can be used to retrieve the Doppler information. By replacing the conventional Fourier transform with the joint time-frequency transform, a 2-D range-Doppler Fourier frame becomes a 3-D time-range-Doppler cube. With sampling in time, a sequence of clear 2-D range-Doppler images can be simply reconstructed without using sophisticated motion compensation